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A066106 a(2n) = (2n)(2n+2); a(2n+1) = 4n + 4. 2
0, 4, 8, 8, 24, 12, 48, 16, 80, 20, 120, 24, 168, 28, 224, 32, 288, 36, 360, 40, 440, 44, 528, 48, 624, 52, 728, 56, 840, 60, 960, 64, 1088, 68, 1224, 72, 1368, 76, 1520, 80, 1680, 84, 1848, 88, 2024, 92, 2208, 96, 2400, 100, 2600, 104, 2808, 108, 3024, 112 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Harry J. Smith, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0,3,0,-3,0,1).

FORMULA

G.f.: 4*x*(-1-2*x+x^2) / ( (x-1)^3*(1+x)^3 ). - Len Smiley, Dec 06 2001

a(n) = 4*A129889(n+1). - R. J. Mathar, Oct 31 2015

MATHEMATICA

Flatten[Table[{(2n)(2n+2), 4n+4}, {n, 0, 30}]] (* Harvey P. Dale, May 14 2011 *)

PROG

(PARI) { for (n=0, 1000, if(n%2, a=2*n + 2, a=n*(n + 2)); write("b066106.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 15 2009

CROSSREFS

Sequence in context: A089474 A141800 A019197 * A030296 A160171 A195752

Adjacent sequences:  A066103 A066104 A066105 * A066107 A066108 A066109

KEYWORD

easy,nonn

AUTHOR

George E. Antoniou, Dec 05 2001

STATUS

approved

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Last modified September 24 03:15 EDT 2021. Contains 347623 sequences. (Running on oeis4.)